Stage 3 heads are the best flowing cylinder heads you can buy for your Z or G. They feature 1mm oversize stainless Ferrea valves with the Ferrea race spring and titanium retainer package. These cylinder heads receive the same high quality port work as the stage 2 heads along with additional work to the combustion chambers. A a five angle grind on the seats which is done on a Serdi head machine to accommodate the 1mm oversize Ferrea valves. These heads are capable of 8000 rpms without the risk of valve float.